engine overheat SUBARU FORESTER 2004 Service Repair Manual

AC-19
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
Diagnostics for A/C System Malfunction
9 CHECK OPERATION OF MAIN FAN MOTOR.
1) Start the engine and turn the A/C switch to
ON.
2) Check the operation of main fan motor.Does the main fan motor oper-
ate normally?Go to step 14.Go to step 10.
10 CHECK POWER SUPPLY TO MAIN FAN MO-
TOR.
CAUTION:
Be careful not to overheat the engine during
repair.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from main fan
motor.
3) Start the engine, and warm it up until
engine coolant temperature increases over
100°C (212°F).
4) Stop the engine and turn ignition switch to
ON.
5) Measure the voltage between main fan
motor harness connector and chassis ground.
Connector & terminal
Except turbo AT model:
(F17) No. 2 (+) — Chassis ground (
−):
Turbo AT model:
(F17) No. 1 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 11.Repair the har-
ness for main fan
motor power sup-
ply circuit.
11 CHECK GROUND CIRCUIT OF MAIN FAN
MOTOR.
Measure the resistance between main fan
motor harness connector and chassis ground.
Connector & terminal
Except turbo AT model:
(F17) No. 1 — Chassis ground:
Turbo AT model:
(F17) No. 2 — Chassis ground:Is the resistance less than 1
Ω?Go to step 12.Repair the har-
ness for main fan
motor ground cir-
cuit.
12 CHECK MAIN FAN MOTOR.
Connect the battery positive (+) terminal to ter-
minal No. 2, and ground (−) terminal to termi-
nal No. 1 of main fan motor connector to make
sure that main fan motor rotate.Does the main fan rotate? Go to step 13.Replace the main
fan motor.
13 CHECK POOR CONTACT IN MAIN FAN MO-
TOR CONNECTOR.
Check poor contact in main fan motor harness
connector.Is there poor contact in con-
nector?Go to step 14.Repair the poor
contact in main fan
motor connector.
14 CHECK OPERATION OF SUB FAN MOTOR.
1) Start the engine and turn the A/C switch to
ON.
2) Check the operation of sub fan motor.Does the sub fan motor oper-
ate normally?Go to step 19.Go to step 15. Step Check Yes No

AC-20
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
Diagnostics for A/C System Malfunction
15 CHECK POWER SUPPLY TO SUB FAN MO-
TOR.
CAUTION:
Be careful not to overheat the engine during
repair.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from sub fan
motor.
3) Start the engine, and warm it up until
engine coolant temperature increases over
100°C (212°F).
4) Stop the engine and turn ignition switch to
ON.
5) Measure the voltage between sub fan
motor harness connector and chassis ground.
Connector & terminal
Except turbo AT model:
(F16) No. 2 (+) — Chassis ground (
−):
Turbo AT model:
(F16) No. 1 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 16.Repair the har-
ness for sub fan
motor power sup-
ply circuit.
16 CHECK GROUND CIRCUIT OF SUB FAN
MOTOR.
Measure the resistance between sub fan motor
harness connector and chassis ground.
Connector & terminal
Except turbo AT model:
(F16) No. 1 — Chassis ground:
Turbo AT model:
(F16) No. 2 — Chassis ground:Is the resistance less than 1
Ω?Go to step 17.Repair the har-
ness for sub fan
motor ground cir-
cuit.
17 CHECK SUB FAN MOTOR.
Connect the battery positive (+) terminal to ter-
minal No. 2, and ground (−) terminal to termi-
nal No. 1 of sub fan motor connector to make
sure that sub fan motor rotate.Does the sub fan motor rotate? Go to step 18.Replace the sub
fan motor.
18 CHECK POOR CONTACT IN SUB FAN MO-
TOR CONNECTOR.
Check poor contact in sub fan motor connec-
tor.Is there poor contact in con-
nector?Go to step 19.Repair the poor
contact in sub fan
motor connector.
19 CHECK POOR CONTACT IN AUTO A/C
CONTROL MODULE CONNECTOR.
Check poor contact in auto A/C control module
connector.Is there poor contact in con-
nector?Replace the auto
A/C control mod-
ule.Repair the con-
nector. Step Check Yes No

PM-20
PERIODIC MAINTENANCE SERVICE
Cooling System
11.Cooling System
A: INSPECTION
1) Check the radiator for leakage, filling it with cool-
ant and attach the radiator cap tester (A) to filler
neck.
PRESSURE:
157 kPa (1.6 kg/cm
2, 23 psi)
Check the following points.
 Each portion of radiator for leakage
 Hose joints and other connections for leakage
CAUTION:
 For turbo model, be sure to install tester to
filler tank side.
 When attaching or detaching tester and when
operating tester, use special care not to deform
radiator filler neck.
 When performing this check, be sure to keep
the engine stationary and fill the radiator with
coolant.
 Wipe off check points before applying pres-
sure.
 Use care not to spill coolant when detaching
the tester from radiator.
 Non-turbo model
 Turbo model
2) Check the radiator cap valve open pressure us-
ing radiator cap tester.
Raise the pressure until the needle of gauge stops
and see if the pressure can be retained for 5 to 6
seconds. The radiator cap is normal if a pressure
above the service limit value has been maintained
for this period.CAUTION:
Rust or dirt on the cap may prevent the valve
from functioning normally: be sure to clean the
cap before testing.
Radiator cap valve open pressure
Standard value:
93 — 123 kPa (0.95 — 1.25 kg/cm2, 14 — 18
psi)
Service limit:
83 kPa (0.85 kg/cm
2, 12 psi)
3) Start the engine, and then check if it does not
over heat or it is cooled excessively. If it overheats
or it is cooled excessively, check the cooling sys-
tem. to CO(H4SO)-26, Thermostat.> CO(H4SO)-28, Radiator.> Radiator Cap.>
4) Check the radiator fan operates using Subaru
Select Monitor, when the coolant temperature ex-
ceeds 95°C (203°F). If not operate, check the radi-
ator fan system. Fan System.>
CO-00042
(A)
CO-00043
(A)
(A) Deformation
(B) Deformation, damage, rust
PM-00023
PM-00089
(B)
(A)(A)

ME(H4SO)-92
MECHANICAL
Engine Trouble in General
4) Engine stalls after initial
combustion. Engine control system A
Intake system Loosened or cracked intake duct B
Loosened or cracked PCV hose C
Loosened or cracked vacuum hose C
Defective intake manifold gasket B
Defective throttle body gasket B
Dirty air cleaner element C
Fuel line Clogged fuel line C
Lack of or insufficient fuel B
Belt Defective B
Defective timing B
Compression Incorrect valve clearance C
Loosened spark plugs or defective gasket C
Loosened cylinder head bolts or defective gasket C
Improper valve seating C
Defective valve stem C
Worn or broken valve spring B
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing B
Improper engine oil (low viscosity) B
2. Rough idle and engine
stallEngine control system A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose A
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve C
Loosened oil filler cap B
Dirty air cleaner element C
Fuel line Defective fuel pump and relay C
Clogged fuel line C
Lack of or insufficient fuel B
Belt Defective timing C
Compression Incorrect valve clearance B
Loosened spark plugs or defective gasket B
Loosened cylinder head bolts or defective gasket B
Improper valve seating B
Defective valve stem C
Worn or broken valve spring B
Worn or stuck piston rings, cylinder and piston B
Incorrect valve timing A
Improper engine oil (low viscosity) B
Lubrication system Incorrect oil pressure B
Defective rocker cover gasket C
Cooling system Overheating C
Others Malfunction of evaporative emission control system A
Stuck or damaged throttle valve B
Accelerator cable out of adjustment C TROUBLE PROBLEM PARTS, ETC. POSSIBLE CAUSE RANK

ME(H4SO)-93
MECHANICAL
Engine Trouble in General
3. Low output, hesitation and
poor accelerationEngine control system A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose B
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve B
Loosened oil filler cap B
Dirty air cleaner element A
Fuel line Defective fuel pump and relay B
Clogged fuel line B
Lack of or insufficient fuel C
Belt Defective timing B
Compression Incorrect valve clearance B
Loosened spark plugs or defective gasket B
Loosened cylinder head bolts or defective gasket B
Improper valve seating B
Defective valve stem C
Worn or broken valve spring B
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing A
Improper engine oil (low viscosity) B
Lubrication system Incorrect oil pressure B
Cooling system Overheating C
Over cooling C
Others Malfunction of evaporative emission control system A
4. Surging Engine control system A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose A
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve B
Loosened oil filler cap B
Dirty air cleaner element B
Fuel line Defective fuel pump and relay B
Clogged fuel line B
Lack of or insufficient fuel C
Belt Defective timing B
Compression Incorrect valve clearance B
Loosened spark plugs or defective gasket C
Loosened cylinder head bolts or defective gasket C
Improper valve seating C
Defective valve stem C
Worn or broken valve spring C
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing A
Improper engine oil (low viscosity) B
Cooling system Overheating B
Others Malfunction of evaporative emission control system C TROUBLE PROBLEM PARTS, ETC. POSSIBLE CAUSE RANK

ME(H4SO)-94
MECHANICAL
Engine Trouble in General
5. Engine does not return to
idle.Engine control system A
Intake system Loosened or cracked vacuum hose A
Others Stuck or damaged throttle valve A
Accelerator cable out of adjustment B
6. Dieseling (Run-on) Engine control system A
Cooling system Overheating B
Others Malfunction of evaporative emission control system B
7. After burning in exhaust
systemEngine control system A
Intake system Loosened or cracked intake duct C
Loosened or cracked PCV hose C
Loosened or cracked vacuum hose B
Defective PCV valve B
Loosened oil filler cap C
Belt Defective timing B
Compression Incorrect valve clearance B
Loosened spark plugs or defective gasket C
Loosened cylinder head bolts or defective gasket C
Improper valve seating B
Defective valve stem C
Worn or broken valve spring C
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing A
Lubrication system Incorrect oil pressure C
Cooling system Over cooling C
Others Malfunction of evaporative emission control system C
8. Knocking Engine control system A
Intake system Loosened oil filler cap B
Belt Defective timing B
Compression Incorrect valve clearance C
Incorrect valve timing B
Cooling system Overheating A
9. Excessive engine oil con-
sumptionIntake system Loosened or cracked PCV hose A
Defective PCV valve B
Loosened oil filler cap C
Compression Defective valve stem A
Worn or stuck piston rings, cylinder and piston A
Lubrication system Loosened oil pump attaching bolts and defective gas-
ketB
Defective oil filter seal B
Defective crankshaft oil seal B
Defective rocker cover gasket B
Loosened oil drain plug or defective gasket B
Loosened oil pan fitting bolts or defective oil pan B TROUBLE PROBLEM PARTS, ETC. POSSIBLE CAUSE RANK

IG(H4SO)-7
IGNITION
Spark Plug
3) Oil fouled:
Wet black deposits show excessive oil entrance
into combustion chamber through worn rings and
pistons or excessive clearance between valve
guides and stems. If the same condition remains
after repair, use a hotter plug.
4) Overheating:
White or light gray insulator with black or gray
brown spots and bluish burnt electrodes indicates
engine overheating. Moreover, the appearance re-
sults from incorrect ignition timing, loose spark
plugs, wrong selection of fuel, hotter range plug,
etc. It is advisable to replace with plugs having
colder heat range.
D: CLEANING
Clean the spark plugs in a sand blast type cleaner.
Avoid excessive blasting. Clean and remove the
carbon or oxide deposits, but do not wear away ce-
ramic insulator.
If deposits are too stubborn, replace the spark
plugs.
E: ADJUSTMENT
Correct it if the spark plug gap is measured with a
gap gauge, and it is necessary.
Spark plug gap: L
1.0 — 1.1 mm (0.039 — 0.043 in)
NOTE:
Replace with a new spark plug if this area (A) is
worn to “ball” shape.
IG-00026
IG-00027
IG-00028
L
(A)

ME(H4DOTC)-119
MECHANICAL
Engine Trouble in General
4) Engine stalls after initial
combustion. Engine control system A
Intake system Loosened or cracked intake duct B
Loosened or cracked PCV hose C
Loosened or cracked vacuum hose C
Defective intake manifold gasket B
Defective throttle body gasket B
Dirty air cleaner element C
Fuel line Clogged fuel line C
Lack of or insufficient fuel B
Belt Defective (deterioration, etc.) B
Defective timing B
Compression Incorrect valve clearance C
Loosened spark plugs or defective gasket C
Loosened cylinder head bolts or defective gasket C
Improper valve seating C
Defective valve stem C
Worn or broken valve spring B
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing B
Improper engine oil (low viscosity) B
2. Rough idle and engine
stallEngine control system A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose A
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve C
Loosened oil filler cap B
Dirty air cleaner element C
Fuel line Defective fuel pump and relay C
Clogged fuel line C
Lack of or insufficient fuel B
Belt Defective timing C
Compression Incorrect valve clearance B
Loosened spark plugs or defective gasket B
Loosened cylinder head bolts or defective gasket B
Improper valve seating B
Defective valve stem C
Worn or broken valve spring B
Worn or stuck piston rings, cylinder and piston B
Incorrect valve timing A
Improper engine oil (low viscosity) B
Lubrication system Incorrect oil pressure B
Defective rocker cover gasket C
Cooling system Overheating C
Others Malfunction of evaporative emission control system A
Stuck or damaged throttle valve B
Accelerator cable out of adjustment C TROUBLE PROBLEM PARTS, ETC. POSSIBLE CAUSE RANK

ME(H4DOTC)-120
MECHANICAL
Engine Trouble in General
3. Low output, hesitation and
poor accelerationEngine control system A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose B
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve B
Loosened oil filler cap B
Dirty air cleaner element A
Fuel line Defective fuel pump and relay B
Clogged fuel line B
Lack of or insufficient fuel C
Belt Defective timing B
Compression Incorrect valve clearance B
Loosened spark plugs or defective gasket B
Loosened cylinder head bolts or defective gasket B
Improper valve seating B
Defective valve stem C
Worn or broken valve spring B
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing A
Improper engine oil (low viscosity) B
Lubrication system Incorrect oil pressure B
Cooling system Overheating C
Over cooling C
Others Malfunction of evaporative emission control system A
4. Surging Engine control system A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose A
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve B
Loosened oil filler cap B
Dirty air cleaner element B
Fuel line Defective fuel pump and relay B
Clogged fuel line B
Lack of or insufficient fuel C
Belt Defective timing B
Compression Incorrect valve clearance B
Loosened spark plugs or defective gasket C
Loosened cylinder head bolts or defective gasket C
Improper valve seating C
Defective valve stem C
Worn or broken valve spring C
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing A
Improper engine oil (low viscosity) B
Cooling system Overheating B
Others Malfunction of evaporative emission control system C TROUBLE PROBLEM PARTS, ETC. POSSIBLE CAUSE RANK

ME(H4DOTC)-121
MECHANICAL
Engine Trouble in General
5. Engine does not return to
idle.Engine control system A
Intake system Loosened or cracked vacuum hose A
Others Stuck or damaged throttle valve A
Accelerator cable out of adjustment (2.0 L model) B
6. Dieseling (Run-on) Engine control system A
Cooling system Overheating B
Others Malfunction of evaporative emission control system B
7. Afterburning in exhaust
systemEngine control system A
Intake system Loosened or cracked intake duct C
Loosened or cracked PCV hose C
Loosened or cracked vacuum hose B
Defective PCV valve B
Loosened oil filler cap C
Belt Defective timing B
Compression Incorrect valve clearance B
Loosened spark plugs or defective gasket C
Loosened cylinder head bolts or defective gasket C
Improper valve seating B
Defective valve stem C
Worn or broken valve spring C
Worn or stuck piston rings, cylinder and piston C
Incorrect valve timing A
Lubrication system Incorrect oil pressure C
Cooling system Over cooling C
Others Malfunction of evaporative emission control system C
8. Knocking Engine control system A
Intake system Loosened oil filler cap B
Belt Defective timing B
Compression Incorrect valve clearance C
Incorrect valve timing B
Cooling system Overheating A
9. Excessive engine oil con-
sumptionIntake system Loosened or cracked PCV hose A
Defective PCV valve B
Loosened oil filler cap C
Compression Defective valve stem A
Worn or stuck piston rings, cylinder and piston A
Lubrication system Loosened oil pump attaching bolts and defective gas-
ketB
Defective oil filter o-ring B
Defective crankshaft oil seal B
Defective rocker cover gasket B
Loosened oil drain plug or defective gasket B
Loosened oil pan fitting bolts or defective oil pan B TROUBLE PROBLEM PARTS, ETC. POSSIBLE CAUSE RANK